Traumatic injury is one of the most common traumatic events worldwide, accounting for approximately 9% of global mortality. Reported rates of post-traumatic stress disorder (PTSD) within the first 6 months of injury range between 10% and 20% in civilian populations and are substantially higher in military personnel returned from combat. Early interventions (such as education or psychological debriefing) for persons exposed to traumatic events have very low success in preventing PTSD, whereas there is evidence that early treatment of acute PTSD with prazosin or other medications or trauma-focused cognitive behavioral therapy can prevent progression to a chronic course of PTSD. Thus, there is great interest in reliable means to identify which persons merit such early treatments, and to longitudinally monitor the evolving status of persons at-risk of developing PTSD or under treatment for PTSD.
There are many challenges to the identification of valid, reliable biomarkers for diagnosing PTSD and assessing its severity. Although many biological abnormalities have been found to be associated with PTSD, including endocrine and neurobiological alterations, there is significant variability in these. PTSD is a multifaceted psychological disorder with symptoms across four psychiatric symptom clusters, and its typology exhibits multiple, distinct longitudinal trajectories encompassing heterogeneous phenotypes. Furthermore, biological (genetic, epigenetic, endocrine, immunological, neurological), environmental (causation and developmental timing of trauma), psychological (cognitive, emotional, behavioral), and social vulnerability factors likely interact in complex ways to affect the risk for PTSD. Given the diagnostic heterogeneity of PTSD and its multifactorial etiology, it is unlikely that a single biomarker will be identified.
Nonetheless, the combination of traditional survey-type questionnaire screening instruments with physiological measures acquired noninvasively via wearable sensors offers promise for higher accuracy. Primary challenges to be confronted involve minimizing stigmatization of the individual being monitored, promoting longitudinal compliance with the monitoring, and arranging signal-processing that achieves useful timeliness and responsiveness to changes in the individual's evolving condition while simultaneously avoiding an excessive rate of false-alarm or Type I errors.